Method and device for hitching an agricultural implement to a three-point lifting system of an agricultural tractor

Abstract

The invention relates to a device for coupling an agricultural implement to an agricultural tractor ( 1 ), comprising two frames ( 10 ) each provided with two base plates ( 11 a ) arranged such that each base plate ( 11 a ) of the frame ( 10 ) carried by the agricultural tractor ( 1 ) is brought into position under the base plate of the frame carried by the agricultural implement, in such a way as to form, with the latter, a pair of base plates consisting of a base plate pierced by a hole of predefined cross-section and dimensions and a base plate ( 11 ) comprising a centering member ( 18, 19 ) of decreasing cross-section starting from a base section of dimensions and cross-section matching those of the hole of the other base plate. In addition, tilting means are designed to cause, in a position where the centering members ( 18, 19 ) are partially engaged with the facing holes, a relative tilting of the two frames during which said centering members serve as the pivot for said tilting.

The invention claimed is: 
     
       1. A method for coupling an agricultural implement ( 3 ) to a three-point linkage system ( 2 ) of an agricultural tractor ( 1 ) of longitudinal axis (x), wherein:
 a coupling device is used comprising two frames ( 10 ,  40 ;  80 ,  100 ) consisting of a coupling frame ( 10 ;  80 ), provided with fastening members ( 16 ,  17   a ;  92 ) for attaching to the three-point linkage system ( 2 ) of the agricultural tractor ( 1 ), and a coupled frame ( 40 ;  100 ), provided with fastening members ( 46 ,  48 ;  106 ,  107 ,  114 ) for attaching to the agricultural implement ( 3 ), both adapted to extend, respectively, transversely to the agricultural tractor ( 1 ) and to the agricultural implement, 
 the coupling is performed, in an initial prepositioning position of the agricultural tractor ( 1 ) relative to the agricultural implement ( 3 ), by maneuvers to pair the two frames ( 10 ,  40 ,  80 ,  100 ), then by a relative locking of said frames, 
 said coupling method being characterized in that: 
 a coupling device is created:
 in which the coupling frame ( 10 ;  80 ) and the coupled frame ( 40 ;  100 ) each comprise two base plates,( 11 ,  53 ,  54 ;  93 ,  118 ,  119 ), arranged at the base of said frames so that the base plates ( 11 ,  53 ,  54 ;  93 ,  118 ,  119 ) of each frame ( 10 ,  40 ;  80 ,  100 ) are spaced apart from each other and aligned along a transverse axis (y), and so that each base plate ( 11 ;  93 ) of the coupling frame ( 10 ;  80 ) forms, with one of the base plates ( 53 ,  54 ;  118 ,  119 ) of the coupled frame ( 40 ;  100 ), a pair of base plates ( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) provided with flat contact faces ( 11   a ,  53   a ;  93   a ,  118   a ) arranged such that the contact face ( 53   a ;  118   a ) of the base plate ( 53 ,  54 ;  118 ,  119 ) of the coupled frame ( 40 ;  100 ) rests on the contact face ( 11   a ;  93   a ) of the base plate ( 11 ;  93 ) of the coupling frame ( 10 ;  80 ) when said frames are in the paired position,
 one of the base plates ( 53 ,  54 ;  118 ,  119 ) of each pair of base plates (( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) being pierced by a facing hole ( 55 ;  120 ) of predetermined cross-section and dimensions, 
 and the other base plate ( 11 ;  93 ) of each pair of base plates ( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) comprising, projecting from a contact face ( 11   a ;  93   a ), a centering member ( 18 ,  19 ;  94 ,  95 ) of decreasing cross-section in at least two planes perpendicular to said contact face and respectively parallel to axes (x) and (y), starting from a base section of dimensions fitting with those of the facing hole ( 55 ;  120 ) of the other base plate ( 53 , 54 ;  118 ,  119 ), 
 
 comprising means ( 9 ;  70 ,  71 ,  75 ) for relative tilting of the two frames ( 10 ,  40 ;  80 ,  100 ), 
 
 and the coupling is carried out in the initial prepositioning position of the agricultural tractor ( 1 ) relative to the agricultural implement ( 3 ), by
 (a) actuating the linkage system ( 2 ) so as to cause each centering member ( 18 ,  19 ) to partially engage with the facing hole ( 55 ,  120 ), by the raising of the coupling frame, 
 then (b) generating the relative tilting of the two frames ( 10 ,  40 ) so as to cause, in the position where the centering members ( 18 ,  19 ;  94 ,  95 ) are partially engaged with the facing holes ( 55 ;  120 ), a tilting during which said centering members serve as a pivot for said tilting, until a final paired position is obtained where the contact faces ( 11   a ,  53   a ;  93   a ,  118   a ) of the base plates ( 11 ,  53 ,  54 ;  93 ,  118 ,  119 ) of each of the two pairs of base plates ( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) are superimposed and in contact with one another, and the centering members ( 18 ,  19 ;  94 ,  95 ) are fully engaged with the facing holes ( 55 ;  120 ). 
 
 
     
     
       2. The coupling method according to  claim 1 , wherein the linkage system ( 2 ) is equipped with a central arm ( 9 ) consisting of an actuating cylinder, and (b) wherein the relative tilting of the two frames ( 10 ,  40 ;  80 ,  100 ) is generated by activating deployment of said cylinder. 
     
     
       3. The coupling method according to  claim 1 , wherein:
 the coupling frame ( 10 ) is equipped with at least one pivot arm ( 70 ,  71 ) pivoting on said coupling frame ( 10 ) about a pivot axis at least substantially parallel to axis (y), positioned at a base of said coupling frame, each of said pivot arms having a hook-shaped end ( 73 ,  74 ) that engages, in the position where the centering members ( 18 ,  19 ) are partially engaged with the facing holes ( 55 ), with a facing catch member ( 52 ) integral with the coupled frame ( 40 ), 
 (b) the relative tilting of the two frames is generated by pivoting each pivot arm ( 70 ,  71 ) so that the respective hook-shaped end ( 73 ,  74 ) travels a path in which the respective hook-shaped end engages the facing catch member ( 52 ), causing the coupling frame ( 10 ) to tilt. 
 
     
     
       4. A device for coupling an agricultural implement ( 3 ) to a three-point linkage system ( 2 ) of an agricultural tractor ( 1 ) of longitudinal axis (x), comprising a coupling device comprising two frames ( 10 ,  40 ;  80 ,  100 ) consisting of a coupling frame ( 10 ;  80 ), provided with fastening members ( 16 ,  17   a ;  92 ) for attaching to the three-point linkage system ( 2 ) of the agricultural tractor ( 1 ), and a coupled frame ( 40 ;  100 ), provided with attachment members ( 46 ,  48 ;  106 ,  107 ,  114 ) for attaching to the agricultural implement ( 3 ), both adapted to extend, respectively, transversely to the agricultural tractor ( 1 ) and to the agricultural implement ( 3 ), said coupling frame and coupled frame being adapted to be paired and comprising relative lock ( 22 ,  23 ,  52 ;  70 ,  71 ,  52 ;  87 ,  109 ,  110 ), said coupling device being characterized in that:
 the coupling frame ( 10 ;  80 ) and the coupled frame ( 40 ;  100 ) each comprise two base plates ( 11 ,  53 ,  54 ;  93 ,  118 ,  119 ), arranged at the base of said frames, so that the base plates ( 11 ,  53 ,  54 ;  93 ,  118 ,  119 ) of each frame ( 10 ,  40 ;  80 ,  100 ) are spaced apart from each other and aligned along a transverse axis (y), and so that each base plate ( 11 ;  93 ) of the coupling frame ( 10 ;  80 ) forms, with one of the base plates ( 53 ,  54 ;  118 ,  119 ) of the coupled frame ( 40 ;  100 ), a pair of base plates ( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) provided with flat contact faces ( 11   a ,  53   a ;  93   a ,  118   a ) arranged such that the contact face ( 53   a ;  118   a ) of the base plate ( 53 ,  54 ;  118 ,  119 ) of the coupled frame ( 40 ;  100 ) rests on the contact face ( 11   a ;  93   a ) of the base plate ( 11 ;  93 ) of the coupling frame ( 10 ;  80 ) when said frames are in the paired position,
 one of the base plates ( 53 ,  54 ;  118 ,  119 ) of each pair of base plates (( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) being pierced by a facing hole ( 55 ;  120 ) of predetermined cross-section and dimensions, 
 and the other base plate ( 11 ;  93 ) of each pair of base plates ( 11 / 53 ,  11 / 54 ;  93 / 118 ,  93 / 119 ) comprising, projecting from its contact face ( 11   a ;  93   a ), a centering member ( 18 ,  19 ;  94 ,  95 ) of decreasing section in at least two planes perpendicular to said contact face and respectively parallel to axes (x) and (y), starting from a base section of dimensions fitting with those of the facing hole ( 55 ;  120 ) of the other base plate ( 53 ,  54 ;  118 ,  119 ), 
 and said base plates being arranged to be brought to face each other so that each centering member ( 18 ,  19 ;  94 ,  95 ) partially engages with the facing hole ( 55 ;  120 ), during the raising of the coupling frame ( 10 ;  80 ) generated by actuation of the three-point linkage system ( 2 ), 
 
 means ( 9 ;  70 ,  71 ,  75 ) for relative tilting of the two frames ( 10 ,  40 ;  80 ,  100 ) are adapted to cause, in the position where the centering members ( 18 ,  19 ;  94 ,  95 ) are partially engaged with the facing holes ( 55 ;  120 ), a tilting during which said centering members serve as a pivot for said tilting. 
 
     
     
       5. The coupling device according to  claim 4 , wherein the means for relative tilting consists of an actuating cylinder ( 9 ) arranged to constitute the central arm of the linkage system ( 2 ). 
     
     
       6. The coupling device according to  claim 5 , wherein the relative lock comprises:
 at least one locking arm ( 22 ) pivoting on the coupling frame ( 10 ), provided with a hook-shaped end ( 23 ) that engages, in the paired position of the two frames ( 10 ,  40 ), with a facing catch member ( 52 ) integral with the coupled frame ( 40 ), 
 means ( 35 ) for actuating each locking arm ( 22 ), able to pivot it between an unlocked position and a locked position where the facing catch member ( 52 ) is locked in place. 
 
     
     
       7. The coupling device according to  claim 5 , wherein the relative lock comprises an actuating cylinder ( 87 ) carried by the coupling frame ( 80 ) so that it extends along a transverse axis orthogonal to axis (x), provided with a rod ( 87   a ) forming a bolt adapted to cooperate with a catch ( 109 ,  110 ) mounted on the coupled frame ( 100 ), when the two frames ( 80 ,  100 ) are in the paired position. 
     
     
       8. The coupling device according to  claim 4 , wherein the means for relative tilting comprise:
 at least one pivot arm ( 70 ,  71 ) pivoting on the coupling frame ( 10 ) about a pivot axis at least substantially parallel to axis (y), positioned at a base of said coupling frame, each of said pivot arms having a hook-shaped end ( 73 ,  74 ) that engages, in the position where the centering members ( 18 ,  19 ) are partially engaged with the facing holes ( 55 ), with a facing catch member ( 52 ) integral with the coupled frame ( 40 ), 
 means ( 75 ) for actuating each pivot arm ( 70 ,  71 ), adapted to pivot the pivot arm so that the respective hook-shaped end ( 73 ,  74 ) travels a path in which the respective hook-shaped end engages the facing catch member ( 52 ), causing the coupling frame ( 10 ) to tilt until the adjoining position of the two frames ( 10 ,  40 ) is obtained. 
 
     
     
       9. The coupling device according to  claim 8 , wherein the hook-shaped end ( 73 ,  74 ) of each pivot arm ( 70 ,  71 ) and each associated catch member ( 52 ) have complementary shapes adapted to lock the two frames ( 10 ,  40 ) in position. 
     
     
       10. The coupling device according to one of  claim 8  or  9 , comprising an actuating cylinder ( 9 ) arranged to constitute the central arm of the linkage system ( 2 ). 
     
     
       11. The coupling device according to one of  claims 4  to  9 , wherein each hole ( 55 ;  120 ) made in a base plate ( 53 ,  54 ;  118 ,  119 ) has a countersink ( 56 ) where it joins the contact face ( 53   a ;  118   a ) of said base plate. 
     
     
       12. The coupling device according to  claim 11 , wherein:
 each hole ( 55 ;  120 ) made in a base plate ( 53 ,  54 ;  118 ,  119 ) consists, in the extension of the countersink ( 56 ), of a hole of constant transverse cross-section, 
 each centering member ( 18 , 19 ;  94 ,  95 ) comprises, starting from the contact face ( 11   a ;  93   a ) of the base plate ( 11 ;  93 ), a base ( 20 ;  96 ) of constant transverse cross-section fitting with that of the facing hole ( 55 ;  120 ). 
 
     
     
       13. The coupling device according to  claim 12 , wherein each centering member ( 18 ,  19 ;  94 ,  95 ) comprises a cylindrical base ( 20 ;  96 ) extending in a section ( 21 ;  97 ) of conical or hemispherical shape, each hole ( 55 ;  120 ) made in a base plate ( 53 ,  54 ;  118 ,  119 ) having a circular cross-section of a diameter fitting with that of the base ( 20 ;  96 ) of the centering members ( 18 ,  19 ;  94 ,  95 ). 
     
     
       14. The coupling device according to one of  claims 4  to  9 , wherein the coupling frame ( 10 ;  80 ) and the coupled frame ( 40 ;  100 ) comprise front faces ( 10   a ,  49   a ;  80   a ,  100   a ) for the contact of said frames in a final adjoining position. 
     
     
       15. The coupling device according to  claim 14 , wherein:
 one of the frames ( 10 ) comprises, projecting from a front contact face ( 10   a ), at least one centering pin ( 26 ,  27 ) of decreasing cross-section along at least one plane perpendicular to said front contact face and parallel to the longitudinal axis (x), 
 the other frame ( 40 ) comprises, for each centering pin ( 26 ,  27 ), a hole ( 57 ,  58 ) opening onto a front face ( 49   a ), having a cross-section suitable for receiving said centering pin. 
 
     
     
       16. The coupling device according to  claim 15 , wherein each centering pin ( 26 ,  27 ) comprises two flat portions ( 30 ) in planes parallel to plane (x, y), each associated hole ( 57 ,  58 ) having flat bearing surfaces for each of said flat portions. 
     
     
       17. The coupling device according to  claim 15 , wherein each centering pin ( 26 ,  27 ) is arranged on an upper portion of the coupling frame ( 10 ). 
     
     
       18. The coupling device according to one of  claims 4  to  9 , comprising:
 complementary drive elements ( 36 ,  61 ) respectively positioned on the coupling frame ( 10 ) and coupled frame ( 40 ) and both adapted to be coupled to universal drive shafts ( 32 ,  60 ) equipping the agricultural tractor ( 1 ) and the agricultural implement ( 3 ), 
 means ( 34 ) for the relative displacement of the complementary drive elements ( 36 ,  61 ), which are able, in the paired position of the two frames ( 10 ,  40 ), to move them between an engaged position where two universal drive shafts ( 32 ,  60 ) are coupled, and a disengaged position. 
 
     
     
       19. The coupling device according to  claim 18 , wherein:
 the drive element ( 61 ) of the coupled frame ( 40 ) is translationally fixed on said coupled frame, 
 the drive element ( 36 ) of the coupling frame ( 10 ) is arranged within a track ( 33 ) having a guide axis parallel to the longitudinal axis (x), attached to said coupling frame, said drive element being associated with means for translational movement ( 34 ) able to move said drive element within the track ( 33 ). 
 
     
     
       20. The coupling device according to  claim 18 , wherein the drive elements respectively comprise a shaft ( 38 ) provided with splines and a shaft ( 63 ) pierced with a longitudinal bore provided with splines, said splines forming complementary engaging teeth.